Method of forming an epitaxial layer on a substrate, and apparatus and system for performing the same

ABSTRACT

In a method of forming an epitaxial layer, an etching gas may be decomposed to form decomposed etching gases. A source gas may be decomposed to form decomposed source gases. The decomposed source gases may be applied to a substrate to form the epitaxial layer on the substrate. A portion of the epitaxial layer on a specific region of the substrate may be etched using the decomposed etching gases. Before the etching gas is introduced into the reaction chamber, the etching gas may be previously decomposed. The decomposed etching gases may then be introduced into the reaction chamber to etch the epitaxial layer on the substrate. As a result, the epitaxial layer on the substrate may have a uniform distribution.

CROSS-RELATED APPLICATION

This application claims priority to and is a divisional application ofU.S. patent application Ser. No. 14/152,191, filed Jan. 10, 2014, whichclaims priority under 35 USC §119 to Korean Patent Application No.10-2013-0002954, filed on Jan. 10, 2013 in the Korean IntellectualProperty Office (KIPO), the contents of which are herein incorporated byreference in their entirety.

BACKGROUND

Generally, a silicon source gas may be applied to a silicon substrate togrow silicon from the silicon substrate, thereby forming an epitaxiallayer. Further, a silicon source gas and an etching gas may be appliedto a silicon substrate to grow silicon from the silicon substrate and toetch the silicon on an insulating layer of the silicon substrate by theetching gas, thereby forming a selective epitaxial layer.

When the etching gas is not in its decomposed form in a reactionchamber, the epitaxial layer on the insulating layer may not be removed.In order to prevent the above-mentioned problem, a single type apparatusmay perform an SEG process at a high temperature. In contrast, a batchtype apparatus may require a great amount of the etching gas. In thebatch type apparatus, the etching gas and the silicon source gas may notbe applied simultaneously. As a result, the epitaxial layer on thesilicon substrate may not have a uniform distribution.

SUMMARY

Example embodiments relate to a method of forming an epitaxial layer,and an apparatus and a system for performing the same. Moreparticularly, example embodiments relate to a method of forming anepitaxial layer on a substrate by a selective epitaxial growth (SEG)process, and an apparatus and a system for performing the method.

Example embodiments provide a method of forming an epitaxial layerhaving a uniform distribution.

Example embodiments also provide an apparatus for forming theabove-mentioned method.

Example embodiments still also provide a system including theabove-mentioned apparatus.

According to some example embodiments, a method of forming an epitaxiallayer on a substrate is provided. In the method of forming the epitaxiallayer, an etching gas may be decomposed to form decomposed etchinggases. A source gas may be decomposed to form decomposed source gases.The decomposed source gases may be applied to a substrate to form theepitaxial layer on the substrate. A portion of the epitaxial layer on aspecific region of the substrate may be etched using the decomposedetching gases.

In example embodiments, decomposing the etching gas includes convertingthe etching gas into plasma.

In example embodiments, the method further includes cooling the sourcegas to prevent the source gas from being decomposed before applying thesource gas to the substrate.

In example embodiments, cooling the source gas includes supplying acooling gas to a cooling unit to cool the source gas.

In example embodiments, the method may further include etching a nativeoxide layer formed on the substrate.

In one embodiment, the method includes performing the decomposing of thesource gas, the applying of the decomposed source gas to the substrate,and the etching a portion of the epitaxial layer in a reaction chamber.

The method may further include decomposing the etching gas to form thedecomposed etching gases prior to supplying the etching gas to thereaction chamber.

In one embodiment, the method further includes forming an epitaxiallayer on a second substrate simultaneously with forming the epitaxiallayer on the substrate by using a multi-substrate receiving structureinserted into the reaction chamber. The multi-substrate receivingstructure may include blocking plates disposed between upper substrateholders and lower substrate holders. In addition, for each blockingplate, an upper substrate holder adjacent the blocking plate above theblocking plate may be further from the blocking plate than a lowersubstrate holder adjacent the blocking plate below the blocking plate.

In one embodiment, the method additionally includes supplying theetching gas and the source gas from a mixed gas line to an injectingunit in the reaction chamber.

The method may further include heating the reaction chamber; andapplying a cooling gas to the injecting unit to cool the etching gas andthe source gas in the injecting unit.

According to some example embodiments, an apparatus is provided forforming an epitaxial layer on a substrate. The apparatus may include areaction chamber, a boat, a heater, an injecting unit and a decomposingunit. The boat may be arranged in the reaction chamber to receive aplurality of substrates. The heater may be provided to the reactionchamber to heat the reaction chamber. The injecting unit may be arrangedin the reaction chamber to inject a source gas and an etching gas to thesubstrates in the boat. The decomposing unit may decompose the etchinggas introduced into the injecting unit.

In example embodiments, the apparatus may further include a cooling unitconfigured to cool the injecting unit to prevent the source gas frombeing decomposed in the injecting unit.

In example embodiments, the cooling unit may include a cooling ductconfigured to surround the injecting unit. A cooling gas may passthrough a passageway between the cooling duct and the injecting unit.

In example embodiments, the cooling duct may have a triple structureincluding a quartz member and an adiabatic member inserted into thequartz member.

In example embodiments, the apparatus may further include an etching gasline connected to the decomposing unit, a mixed gas line connectedbetween the decomposing unit and the injecting unit, and a source gasline connected to the mixed gas line. The etching gas may pass throughthe etching gas line. The decomposed etching gases and the source gasmay pass through the mixed gas line. The source gas may pass through thesource gas line.

In example embodiments, the apparatus may further include an etching gasline connected to the decomposing unit, a decomposed etching gas lineextended from the decomposing unit, and a source gas line. The etchinggas may pass through the etching gas line. The decomposed etching gasesmay pass through the decomposed etching gas line. The source gas maypass through the source gas line. The injecting unit may further includea first injector connected to the source gas line to inject the sourcegas, and a second injector connected to the decomposed etching gas lineto inject the decomposed etching gases.

In example embodiments, the boat may include a boat body configured toreceive the substrates, a substrate holder formed on an inner surface ofthe boat body to support lower edge portions of the substrates, and aplurality of blocking plates arranged between the substrate holders toblock interferences between the substrates. The substrate holders may bearranged by the same vertical interval. Each of the blocking plates maybe positioned closer to an adjacent upper substrate holder than anadjacent lower substrate holder.

In example embodiments, the boat may include a boat body configured toreceive the substrates, a plurality of blocking plates horizontallyformed on an inner surface of the boat body to block interferencesbetween the substrates, and supporting pins formed on upper surfaces ofthe blocking plates to support lower surfaces of the substrates.

According to some example embodiments, there may be provided a systemfor forming an epitaxial layer. The system may include a plurality ofloadlock chambers, an etching chamber, a plurality of apparatuses forforming the epitaxial layer and a transfer chamber. A plurality ofsubstrates may be on standby in the loadlock chambers. The etchingchamber may be arranged in front of the loadlock chambers to removenative oxide layers on the substrates. The apparatuses may be arrangedin front of the loadlock chambers to form the epitaxial layers on thesubstrates. The transfer chamber may be arranged between the loadlockchambers and the etching chamber, and between the apparatuses totransfer the substrates. The apparatuses may include a reaction chamber,a boat, a heater, an injecting unit and a decomposing unit. The boat maybe arranged in the reaction chamber to receive a plurality ofsubstrates. The heater may be provided to the reaction chamber to heatthe reaction chamber. The injecting unit may be arranged in the reactionchamber to inject a source gas and an etching gas to the substrates inthe boat. The decomposing unit may decompose the etching gas introducedinto the injecting unit.

In example embodiments, the etching chamber and the apparatuses may bearranged in parallel with each other.

According to example embodiments, before the etching gas may beintroduced into the reaction chamber, the etching gas may be previouslydecomposed. The decomposed etching gases may then be introduced into thereaction chamber to etch the epitaxial layer on the substrate. Thus, theepitaxial layer on the substrate may have a uniform distribution.

Further, the source gas may not be decomposed in the injecting unitbecause the cooling unit may cool the injecting unit so that injectingholes of the injecting unit are not clogged with the decomposed sourcegases decomposed in the injecting unit.

Furthermore, the system may include the loadlock chambers, the etchingchamber and the batch type apparatuses having a clustered structure sothat the epitaxial layers having the uniform distribution may besimultaneously formed on the substrates.

BRIEF DESCRIPTION OF THE DRAWINGS

Example embodiments will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings. FIGS. 1 to 10 represent non-limiting, example embodiments asdescribed herein.

FIG. 1 is a cross-sectional view illustrating an apparatus for formingan epitaxial layer in accordance with example embodiments;

FIG. 2 is an exemplary cross-sectional view taken along a line II-II′ inFIG. 1;

FIG. 3 is an exemplary enlarged cross-sectional view of a portion III inFIG. 2 illustrating a cooling unit of the apparatus;

FIG. 4 is a cross-sectional view illustrating a cooling unit of anapparatus in accordance with example embodiments;

FIG. 5 is an exemplary enlarged cross-sectional view illustrating a boatof the apparatus in FIG. 1;

FIG. 6 is a cross-sectional view illustrating a boat of an apparatus inaccordance with example embodiments;

FIG. 7 is a cross-sectional view illustrating an apparatus for formingan epitaxial layer in accordance with example embodiments;

FIG. 8 is an exemplary plan view illustrating a system for forming anepitaxial layer including the apparatus in FIG. 1;

FIG. 9 is a flow chart illustrating a method of forming an epitaxiallayer using the apparatus in FIG. 1 and the system in FIG. 8, accordingto certain exemplary embodiments; and

FIG. 10 is a flow chart illustrating a method of forming an epitaxiallayer using the apparatus in FIG. 7 and the system in FIG. 8, accordingto certain exemplary embodiments.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Various example embodiments will be described more fully hereinafterwith reference to the accompanying drawings, in which some exampleembodiments are shown. The present invention may, however, be embodiedin many different forms and should not be construed as limited to theexample embodiments set forth herein. In the drawings, the sizes andrelative sizes of layers and regions may be exaggerated for clarity.

It will be understood that when an element or layer is referred to asbeing “on,” “connected to” or “coupled to” another element or layer, itcan be directly on, connected or coupled to the other element or layeror intervening elements or layers may be present. In contrast, when anelement is referred to as being “directly on,” “directly connected to”or “directly coupled to” another element or layer, there are nointervening elements or layers present. Like numerals refer to likeelements throughout. As used herein, the term “and/or” includes any andall combinations of one or more of the associated listed items.

It will be understood that, although the terms first, second, third etc.may be used herein to describe various elements, components, regions,layers and/or sections, these elements, components, regions, layersand/or sections should not be limited by these terms. Unless indicatedotherwise, these terms are only used to distinguish one element,component, region, layer or section from another region, layer orsection. Thus, a first element, component, region, layer or sectiondiscussed below could be termed a second element, component, region,layer or section without departing from the teachings of the presentinvention.

Spatially relative terms, such as “beneath,” “below,” “lower,” “above,”“upper” and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if the device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features would then be oriented “above” the other elementsor features. Thus, the exemplary term “below” can encompass both anorientation of above and below. The device may be otherwise oriented(rotated 90 degrees or at other orientations) and the spatially relativedescriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing particularexample embodiments only and is not intended to be limiting of thepresent invention. As used herein, the singular forms “a,” “an” and“the” are intended to include the plural forms as well, unless thecontext clearly indicates otherwise. It will be further understood thatthe terms “comprises” and/or “comprising,” when used in thisspecification, specify the presence of stated features, integers, steps,operations, elements, and/or components, but do not preclude thepresence or addition of one or more other features, integers, steps,operations, elements, components, and/or groups thereof.

Example embodiments are described herein with reference tocross-sectional illustrations that are schematic illustrations ofidealized example embodiments (and intermediate structures). As such,variations from the shapes of the illustrations as a result, forexample, of manufacturing techniques and/or tolerances, are to beexpected. Thus, example embodiments should not be construed as limitedto the particular shapes of regions illustrated herein but are toinclude deviations in shapes that result, for example, frommanufacturing. For example, an region illustrated as a rectangle will,typically, have slightly rounded or curved features. Thus, the regionsillustrated in the figures are schematic in nature and their shapes arenot intended to limit the scope of the present invention.

Terms such as “same,” “equidistant,” or “parallel,” as used herein whenreferring to orientation, layout, location, shapes, sizes, amounts, orother measures do not necessarily mean an exactly identical orientation,layout, location, shape, size, amount, or other measure, but areintended to encompass nearly identical orientation, layout, location,shapes, sizes, amounts, or other measures within acceptable variationsthat may occur, for example, due to manufacturing processes.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

Hereinafter, example embodiments will be explained in detail withreference to the accompanying drawings.

Apparatus for Forming an Epitaxial Layer

FIG. 1 is a cross-sectional view illustrating an apparatus for formingan epitaxial layer in accordance with example embodiments, FIG. 2 is across-sectional view taken along a line II-II′ in FIG. 1, FIG. 3 is anenlarged cross-sectional view of a portion III in FIG. 2 illustrating acooling unit of the apparatus, FIG. 4 is a cross-sectional viewillustrating a cooling unit of an apparatus in accordance with exampleembodiments, FIG. 5 is an enlarged cross-sectional view illustrating aboat of the apparatus in FIG. 1, and FIG. 6 is a cross-sectional viewillustrating a boat of an apparatus in accordance with exampleembodiments.

Referring to FIG. 1, an apparatus 100 for forming an epitaxial layer inaccordance with this example embodiment may include a reaction chamber110, a boat 120, a heater 130, an injecting unit 140 and a decomposingunit 150.

The reaction chamber 110 may have an inner space configured to receive aplurality of semiconductor substrates S, a source gas and an etchinggas. The epitaxial layer may be formed on an upper surface of each ofthe semiconductor substrates S using the source gas and the etching gas.In example embodiments, the reaction chamber 110 has a cylindricalshape. Alternatively, the reaction chamber 110 may have a rectangularparallelepiped shape.

The heater 130 may be installed on an outer surface of the reactionchamber 110. The heater 130 may heat the inner space of the reactionchamber 110 to decompose the source gas and the etching gas. Referringto FIG. 2, the heater 130 may have a coiled shape configured to surroundthe outer surface of the reaction chamber 110. Alternatively, the heater130 may be arranged in the inner space of the reaction chamber 110.Further, the heater 130 may be built in a wall of the reaction chamber110.

The boat 120 may be arranged in the inner space of the reaction chamber110. The boat 120 may be configured to receive the semiconductorsubstrates S. The semiconductor substrates S may be horizontally placedin an inner space of the boat 120.

In example embodiments, referring to FIG. 5, the boat 120 may include aboat body 122, substrate holders 124 and blocking plates 126. The boatbody 122 may have the inner space configured to receive thesemiconductor substrates S. The substrate holders 124 may be extendedfrom an inner surface of the boat 122 to support lower edge portions ofthe semiconductor substrates S. The boat 120 may also be referred to asa multi-substrate receiving structure having outer walls, blockingplates, and substrate support members.

In example embodiments, the substrate holders 124 are arranged bysubstantially the same vertical interval. Thus, the semiconductorsubstrates S on the substrate holders 124 may also be arranged bysubstantially the same vertical interval. When intervals between thesubstrate holders 124 are different from each other, the semiconductorsubstrates S on the substrate holders 124 may be arranged by differentintervals. In this case, upper spaces over the different semiconductorsubstrates S may have different volumes. The source gases and theetching gases distributed in the upper spaces having the differentvolumes may have different amounts. As a result, the epitaxial layers onthe different semiconductor substrates S may not have a uniformdistribution. In one embodiment, in order to provide the epitaxiallayers with the uniform distribution, the semiconductor substrates S areprovided with the substantially the same vertical interval between them.In one embodiment, the vertical interval between the substrate holders124 may be substantially the same.

The blocking plates 126 may be extended from the inner surface of theboat body 122. The blocking plates 126 may be arranged between thesubstrate holders 124. Each of the blocking plates 126 may divide theupper spaces over the each of the semiconductor substrates S into twospaces to block interferences between the semiconductor substrates S.When the blocking plates 126 do not exist between the semiconductorsubstrates S, the source gas introduced into the spaces between thesemiconductor substrates S may be applied to a lower surface of an uppersemiconductor substrate as well as an upper surface of a lowersemiconductor substrate to form an undesired epitaxial layer on thelower surface of the upper semiconductor substrate. Further, because asufficient amount of the source gas may not be applied to the lowersemiconductor substrate, the epitaxial layer having a desired thicknessmay not be formed on the lower semiconductor substrate. Thus, theblocking plates 126 between the semiconductor substrates S may block theinterferences between the semiconductor substrates S. In exampleembodiments, the blocking plates 126 may be arranged by substantiallythe same vertical interval. In relation to a particular blocking plate126, an upper semiconductor substrate may be referred to as an overheadsemiconductor substrate, located above the blocking plate 126, and alower semiconductor substrate may be referred to as an underneathsemiconductor substrate, located below the blocking plate 126.

In example embodiments, a distance D1 between the blocking plate 126 andthe upper semiconductor substrate S may be shorter than a distance D2between the blocking plate 126 and the lower semiconductor substrate S.For example, the blocking plate 126 may be positioned closer to an uppersubstrate holder 124 for supporting the upper semiconductor substrate Sthan a lower substrate holder 124 for supporting the lower semiconductorsubstrate S. Thus, more semiconductor substrates S may be received inthe boat 120 than in prior art systems. Particularly, a height of theboat 120 may be restricted by a height of the reaction chamber 110.Further, in certain embodiments, in order to form the epitaxial layerhaving the desired thickness, the space between the lower semiconductorsubstrate S and the blocking plate 126 may need to have a certainvolume, for example, above a particular threshold. In contrast, anamount of the source gas introduced into the space between the uppersemiconductor substrate S and the blocking plate 126 may have norelation to the formation of the epitaxial layer. As such, the spacebetween the upper semiconductor substrate S and the blocking plate 126may not have a volume limit. Therefore, a greater number of substrateholders 124 may be arranged in the boat 120 by setting the distance D1between the upper semiconductor substrate S (or upper substrate holder124) and the blocking plate 126 shorter than the distance D2 between thelower semiconductor substrate S (or lower substrate holder 124) and theblocking plate 126. As a result, the epitaxial layers may besimultaneously formed on a great amount of the semiconductor substratesS by a single process.

Alternatively, referring to FIG. 6, a boat 120 a may include a boat body122, blocking plates 126 and supporting pins 128. The boat body 122 andthe blocking plates 126 in FIG. 6 may have functions and shapessubstantially the same as those of the boat body 122 and the blockingplates 126 in FIG. 5. Thus, any further illustrations with respect tothe boat body 122 and the blocking plates 126 in FIG. 6 are omittedherein for brevity. The supporting pins 128 may be vertically formed onupper surfaces of the blocking plates 126 to support the lower surfacesof the semiconductor substrates S.

Referring to FIG. 1, the injecting unit 140 may be arranged between theouter walls of the reaction chamber 110 and the boat 120. The injectingunit 140 may have a plurality of injecting holes 142 configured toinject the source gas and the etching gas to the inner space of thereaction chamber 110. Referring to FIG. 2, a plurality of injectors ofthe injecting unit 140 may be arranged in the reaction chamber 110, suchas on the circular inner surface of the reaction chamber 110. Theinjecting unit 140 or an individual injector may be referred to hereinmore generally as a supply unit. In the embodiment of FIG. 1, a supplyunit for supplying source gas and etch gas to the chamber includes aplurality of openings for supplying the source gas and the etching gasto the chamber 110.

In example embodiments, the apparatus 100 further includes one or morecooling units 160. In one embodiment, each cooling unit 160 may cool aninjector of the injecting unit 140 to prevent the source gas from beingdecomposed in the injecting unit 140. Thus, the injecting holes 142 maynot be clogged with decomposed source gases. In one embodiment, in thecase where a plurality of injectors are included, a plurality ofrespective cooling units 160 may also be included.

Referring to FIG. 3, the cooling unit 160 may include a cooling ductconfigured to surround the injecting unit 140. The injecting holes 142may be exposed from the cooling duct 160. A cooling gas may pass througha passageway between the cooling duct 160 and the injecting unit 140 tocool the source gas in the injecting unit 140. Thus, as shown in FIG. 1,a cooling gas line 176 may be connected to the cooling duct 160. Inexample embodiments, the cooling gas may include a nitrogen gas.

In example embodiments, because the injecting unit 140 is positioned inthe inner space of the reaction chamber 110 heated by the heater 130,the heat generated from the heater 130 may be transferred to theinjecting unit 140. In order to prevent the transfer of the heat, thecooling duct 160 may be positioned between the heater 130 and aninjector of the injecting unit 140. Also, the cooling duct 160 may havea triple structure including a quartz member 162 and an adiabatic member164 inserted into the quartz member 162. Alternatively, the cooling duct160 may include only the adiabatic member 164.

In example embodiments, when the reaction chamber 110 has thecylindrical shape, the inner surface of the reaction chamber 110 mayalso have the circular shape. Thus, the cooling duct 160 may have acurved shape having a curvature substantially the same as that of theinner surface of the reaction chamber 110.

Alternatively, as shown in FIG. 4, when the reaction chamber 110 has therectangular parallelepiped shape, the inner surface of the reactionchamber 110 may have a linear shape. Thus, a cooling duct 160 a may havea linear shape corresponding to the linear inner surface of the reactionchamber 110.

Referring to FIG. 1, the decomposing unit 150 may be connected with theinjecting unit 140 via a mixed gas line 174. The mixed gas line 174 maybe connected to a source gas line 170. Thus, the source gas may besupplied to the injecting unit 140 through the source gas line 170 andthe mixed gas line 174.

The decomposing unit 150 may be connected to an etching gas line 172.The decomposing unit 150 may decompose the etching gas supplied throughthe etching gas line 172. That is, the decomposing unit 150 maypreviously decompose the etching gas before the etching gas isintroduced into the reaction chamber 110. Therefore, the decomposedetching gases and the source gas may be supplied to the injecting unit140 through the mixed gas line 174. The injecting unit 140 may injectthe decomposed etching gases and the source gas into the reactionchamber 110. In example embodiments, the decomposing unit 150 includes aplasma processing unit configured to convert the etching gas intoplasma.

Because of the cooling units 160, a large amount of the etching gasinjected into the reaction chamber 110 may not be decomposed by the heatof the heater 130. As a result, a portion of the epitaxial layer on adesired portion of the semiconductor substrate S, for example on aninsulating layer of the semiconductor substrate, may not be completelyremoved. In addition, the epitaxial layer on the semiconductor substrateS may not have uniform distribution. Therefore, in example embodiments,the decomposing unit 150 may previously decompose the etching gas. Thus,a sufficient amount of the decomposed etching gases may be applied tothe semiconductor substrates S so that the portion of the epitaxiallayer on the insulating layer may be completely removed. As a result,the epitaxial layer on the semiconductor substrate S may have theuniform distribution.

In example embodiments, the cooling gas for cooling the injecting unit140 may have a temperature at which the decomposed etching gases may notbe bonded to each other. For example, when the temperature is at acooling temperature above a particular threshold, the decomposed etchinggases may not be bonded to each other.

In example embodiments, the etching gas may include a hydrogen chloride(HCL) gas. The source gas may include an SiH₄ gas, an SiH₂Cl₂ gas, etc.

According to this example embodiment, the etching gas may be previouslydecomposed. Thus, the batch type apparatus may be capable of togetherproviding the source gas and the etching gas to the reaction chamber.

FIG. 7 is a cross-sectional view illustrating an apparatus for formingan epitaxial layer in accordance with example embodiments.

An apparatus 100 a of this example embodiment may include elementssubstantially the same as those of the apparatus 100 in FIG. 1 exceptfor an injecting unit. Thus, the same reference numerals may refer tothe same elements and any further illustrations with respect to the sameelements may be omitted herein for brevity.

Referring to FIG. 7, an injecting unit 140 a of this example embodimentmay include at least a first injector 144 and at least a second injector146. The first injector 144 may inject only the source gas into thereaction chamber 110. Thus, only the source gas line 170 may beconnected to the first injector 144. Further, the cooling unit 160 maybe provided to only the first injector 144 and not to the secondinjector. Though one first injector 144 and one second injector 146 areshown, additional first injectors and additional second injectors may beincluded in the apparatus 100 a.

In one embodiment, the second injector 146 injects only the decomposedetching gases into the reaction chamber 110. Thus, the decomposing unit150 may be connected with the second injector 146 via the decomposedetching gas line 178. The etching gas line 172 may be connected to thedecomposing unit 150. In contrast, the cooling unit 160 may not beprovided to the second injector 146.

In example embodiments, because only the source gas is supplied to thefirst injector 144, the cooling unit 160 may cool the source gas to asufficiently low temperature. Thus, the clogging of the injecting holes142 caused by the source gas decomposed in the first injector 144 may becompletely prevented.

In contrast, because the cooling unit 160 is not provided to the secondinjector 146, the bonding of the decomposed etching gases in the secondinjector 146 caused by the cooling unit 160 may be completely prevented.

System for Forming an Epitaxial Layer

FIG. 8 is a plan view illustrating a system for forming an epitaxiallayer including the apparatus in FIG. 1, according to one exemplaryembodiment.

Referring to FIG. 8, a system 200 for forming an epitaxial layer inaccordance with this example embodiment may include two apparatuses 100for forming the epitaxial layer, three loadlock chambers 210, an etchingchamber 220 and a transfer chamber 230.

In example embodiments, the etching chamber 220 and the apparatuses 100may face the loadlock chambers 210. For example, the etching chamber 220and the apparatuses 100 may have front doors facing front doors of theloadlock chambers 210. The transfer chamber 230 may be positionedbetween the etching chamber 220 and the apparatuses 100.

The etching chamber 220 and the apparatuses 100 may be sequentiallyarranged. Further, the etching chamber 220 and the apparatuses 100 maybe parallel to each other. The transfer chamber 230 may have arectangular horizontal cross-section.

In example embodiments, the apparatuses 100 may have a structuresubstantially the same as that of the apparatuses 100 in FIG. 1. Thus,any further illustrations with respect to the apparatuses 100 may beomitted herein for brevity. Alternatively, the system 200 may includethe apparatus 100 a in FIG. 7 in place of the apparatus 100 in FIG. 1.

As mentioned above, the apparatuses 100 may correspond to a batch typeapparatus for simultaneously forming the epitaxial layers on thesemiconductor substrates. Thus, the system 200 may have a clusteredstructure where the loadlock chambers 210, the etching chamber 220 andthe batch type apparatuses 100 may be arranged at both sides of thetransfer chamber 230. Particularly, because the system 200 may have arectangular parallelepiped structure, a space where the system 200 mayoccupy may be minimized.

The semiconductor substrates on which the epitaxial layers are to beformed may be on standby in the loadlock chambers 210. The semiconductorsubstrates on which the epitaxial layers may be formed may be unloadedfrom the apparatuses 100 to the loadlock chambers 210. Processconditions corresponding to those for forming the epitaxial layer may beset in the loadlock chambers 210.

The transfer chamber 230 may have a transfer robot 232. The transferrobot 232 may transfer the semiconductor substrates from the loadlockchambers 210 to the etching chamber 220.

The etching chamber 220 may etch native oxide layers formed on thesemiconductor substrates. In example embodiments, the etching chamber220 may include a plasma etching chamber for etching the native oxidelayers using the plasma.

The transfer robot 232 may transfer the semiconductor substrates fromthe etching chamber 220 to the apparatuses 100. The apparatuses 100 mayform the epitaxial layers on the semiconductor substrates. In exampleembodiments, the apparatuses 100 may be repaired through rear doors ofthe apparatuses 100.

The transfer robot 232 may unload the semiconductor substrates on whichthe epitaxial layers may be formed to the loadlock chambers 210.

Method of Forming an Epitaxial Layer

FIG. 9 is a flow chart illustrating an exemplary method of forming anepitaxial layer using the apparatus in FIG. 1 and the system in FIG. 8,according to one embodiment.

Referring to FIGS. 1, 8 and 9, in step ST300, the transfer chamber 230transfers the semiconductor substrates to the etching chamber 220.

In step ST302, the etching chamber 220 etches the native oxide layers onthe semiconductor substrates using the plasma.

In step ST304, the transfer chamber 230 loads the semiconductorsubstrates from the etching chamber 220 to the boat 120 in the reactionchamber 110. The semiconductor substrates may be placed on the substrateholders 124 of the boat 120.

In step ST306, the heater 130 heats the reaction chamber 110 to providethe inner space of the reaction chamber 110 with a temperature at whichthe epitaxial layer may be formed.

In step ST308, the decomposing unit 150 decomposes the etching gas toform decomposed etching gases. In example embodiments, the etching gasmay include HCl so that the decomposed etching gases may include an Hgas and a Cl gas.

In step ST310, the decomposed etching gas and the source gas aresupplied to the injecting unit 140 through the mixed gas line 174.

In step ST312, the cooling unit 160 cools the injecting unit 140 toprevent the source gas from being decomposed in the injecting unit 140.In example embodiments, the nitrogen gas may pass through the passagewaybetween the cooling duct 160 and the injecting unit 140 to cool thesource gas. In contrast, the nitrogen gas may have a temperature atwhich the decomposed etching gases may not be bonded to each other.Therefore, the temperature of the cooling unit may be set to a valuecool enough to prevent most source gases from being decomposed, butstill warm enough to prevent most of the etching gas from being bondedto each other.

In step ST314, the injecting unit 140 injects the decomposed etchinggases and the source gas into the reaction chamber 110.

In step ST316, the injected source gas is decomposed in the heatedreaction chamber 110. In example embodiments, the source gas may includean SiH₄ gas or an SiH₂Cl₂ gas, the decomposed source gases may includean Si gas and an H gas and/or an HCl gas.

In step ST318, the decomposed source gases are deposited on thesemiconductor substrates to form the epitaxial layers on thesemiconductor substrates.

In step ST320, the decomposed etching gases etch portions of theepitaxial layers on the insulating layers of the semiconductorsubstrates. In example embodiments, forming the epitaxial layer andetching the epitaxial layer may be performed simultaneously with eachother.

In step ST322, the transfer chamber 230 unloads the semiconductorsubstrates from the reaction chamber 110 to the loadlock chambers 210.

FIG. 10 is a flow chart illustrating an exemplary method of forming anepitaxial layer using the apparatus in FIG. 7 and the system in FIG. 8,according to one embodiment.

Referring to FIGS. 7, 8 and 10, in step ST400, the transfer chamber 230transfers the semiconductor substrates to the etching chamber 220.

In step ST402, the etching chamber 220 etches the native oxide layers onthe semiconductor substrates using the plasma.

In step ST404, the transfer chamber 230 loads the semiconductorsubstrates from the etching chamber 220 to the boat 120 in the reactionchamber 110. The semiconductor substrates may be placed on the substrateholders 124 of the boat 120.

In step ST406, the heater 130 heats the reaction chamber 110 to providethe inner space of the reaction chamber 110 with a temperature at whichthe epitaxial layer may be formed.

In step ST408, the source gas is supplied to the first injector 144.

In step ST410, the cooling unit 160 cools the first injector 144 toprevent the source gas from being decomposed in the first injector 144.

In step ST412, the decomposing unit 150 decomposes the etching gas toform decomposed etching gases. In example embodiments, the etching gasmay include HCl so that the decomposed etching gases may include an Hgas and a Cl gas.

In step ST414, the first injector 144 injects the source gas into thereaction chamber 110.

In step ST416, the second injector 146 injects the decomposed etchinggases into the reaction chamber 110. In example embodiments, injectingthe source gas and injecting the decomposed etching gases may beperformed simultaneously with each other.

In step ST418, the injected source gas is decomposed in the heatedreaction chamber 110. In example embodiments, the source gas may includean SiH₄ gas or an SiH₂Cl₂ gas, the decomposed source gases may includean Si gas and an H gas and/or an HCl gas.

In step ST420, the decomposed source gases are deposited on thesemiconductor substrates to form the epitaxial layers on thesemiconductor substrates.

In step ST422, the decomposed etching gases etch portions of theepitaxial layers on the insulating layers of the semiconductorsubstrates. In example embodiments, forming the epitaxial layer andetching the epitaxial layer may be performed simultaneously with eachother.

In step ST424, the transfer chamber 230 unloads the semiconductorsubstrates from the reaction chamber 110 to the loadlock chambers 210.

According to certain example embodiments, before the etching gas isintroduced into the reaction chamber, the etching gas is previouslydecomposed. The decomposed etching gases may then be introduced into thereaction chamber to etch the epitaxial layer on the substrate. Thus, theepitaxial layer on the substrate may have a uniform distribution.

Further, the source gas may not be decomposed in the injecting unitbecause the cooling unit may cool the injecting unit so that injectingholes of the injecting unit are not clogged with the decomposed sourcegases decomposed in the injecting unit.

Furthermore, the system may include the loadlock chambers, the etchingchamber and the batch type apparatuses having a clustered structureincluding blocking plates so that the epitaxial layers having theuniform distribution may be simultaneously formed on the substrates.

The foregoing is illustrative of example embodiments and is not to beconstrued as limiting thereof. Although a few example embodiments havebeen described, those skilled in the art will readily appreciate thatmany modifications are possible in the example embodiments withoutmaterially departing from the novel teachings and advantages of thepresent disclosure. Accordingly, all such modifications are intended tobe included within the scope of the present invention as defined in theclaims. In the claims, means-plus-function clauses are intended to coverthe structures described herein as performing the recited function andnot only structural equivalents but also equivalent structures.Therefore, it is to be understood that the foregoing is illustrative ofvarious example embodiments and is not to be construed as limited to thespecific example embodiments disclosed, and that modifications to thedisclosed example embodiments, as well as other example embodiments, areintended to be included within the scope of the appended claims.

What is claimed is:
 1. An apparatus for forming an epitaxial layer on asubstrate, the apparatus comprising: a reaction chamber; a boat arrangedin the reaction chamber and configured to receive a plurality ofsubstrate; a heater provided to the reaction chamber to heat thereaction chamber; an injecting unit arranged in the reaction chamber toinject a source gas and an etching gas to the substrates in the boat; acooling unit for cooling the injecting unit to prevent the source gasfrom being decomposed in the injecting unit; a decomposing unit fordecomposing the etching gas introduced into the injecting unit to formdecomposed etching gases; an etching gas line connected to thedecomposing unit to supply the etching gas to the decomposing unit; amixed gas line connected between the injecting unit and the decomposingunit to supply the decomposed etching gases and the source gas to theunit; and a source gas line connected to the mixed gas line to supplythe source gas.
 2. The apparatus of claim 1, wherein the cooling unitcomprises a cooling duct configured to surround the injecting unit, anda cooling gas passes through a passageway between the cooling duct andthe injecting unit.
 3. An apparatus for forming an epitaxial layer on asubstrate, the apparatus comprising: a reaction chamber; a boat arrangedin the reaction chamber and configured to receive a plurality ofsubstrate; a heater provided to the reaction chamber to heat thereaction chamber; an injecting unit arranged in the reaction chamber toinject a source gas and an etching gas to the substrates in the boat; acooling unit for cooling the injecting unit to prevent the source gasfrom being decomposed in the injecting unit; a decomposing unit fordecomposing the etching gas introduced into the injecting unit to formdecomposed etching gases; an etching gas line connected to thedecomposing unit to supply the etching gas to the decomposing unit; adecomposed etching gas line extended from the decomposing unit to supplythe decomposed etching gases; and a source gas line for supplying thesource gas, wherein the injecting unit comprises: a first injectorconnected to the source gas line to inject the source gas; and a secondinjector connected to the decomposed etching gas line to inject thedecomposed etching gases.
 4. The apparatus of claim 1, wherein the boatcomprises: a boat body configured to receive the substrates; substrateholders formed on an inner surface of the boat body to support loweredge portions of the substrates; and blocking plates arranged betweenthe substrate holders to block interferences between the substrates,wherein the substrate holders are arranged by the same verticalinterval, and each of the blocking plates is positioned closer to anadjacent upper substrate holder than an adjacent lower substrate holder.5. A system for forming an epitaxial layer, the system comprising: aplurality of loadlock chambers in which a plurality of substrates is onstandby; a plasma etching chamber arranged in front of the plurality ofloadlock chambers to remove native oxide layers on the substrates;apparatuses arranged in front of the plurality of loadlock chambers toform the epitaxial layer on the substrates; and a transfer chamberarranged between the plurality of loadlock chambers and the plasmaetching chamber and between the plurality of loadlock chambers and theapparatuses to transfer the substrates, wherein each of the apparatusescomprises; a reaction chamber; a boat arranged in the reaction chamberand configured to receive the substrates; a heater provided to thereaction chamber to heat the reaction chamber; an injecting unitarranged in the reaction chamber to inject a source gas and an etchinggas to the substrates in the boat; a cooling unit for cooling theinjecting unit to prevent the source gas from being decomposed in theinjecting unit; and a decomposing unit for decomposing the etching gasintroduced into the injecting unit to form decomposed etching gases; anda decomposed etching gas line extended from the decomposing unit tosupply the decomposed etching gases.